


Fuck, Mate, Kill

by omegadeanlovesalphacas



Category: Supernatural
Genre: Alpha Castiel, Alpha/Beta/Omega Dynamics, Alpha/Omega, Assassin Dean, Badass AND submissive Dean, Biting, Claiming, Collars, Dominant Castiel, Knotting, M/M, Mafia Boss Castiel, Marking, Omega Dean, Seduction, Slut Shaming
Language: English
Status: Completed
Published: 2016-11-21
Updated: 2016-11-21
Packaged: 2018-09-01 07:22:12
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,332
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8614882
Author URL: https://archiveofourown.org/users/omegadeanlovesalphacas/pseuds/omegadeanlovesalphacas
Summary: Dean is an omega assassin sent to kill alpha mafia boss Castiel. When Castiel turns out to be Dean's true mate, plans suddenly change.





	

**Author's Note:**

> Warning! This is an Alpha/omega kink prompt fill. Expect more porn than plot, and lots of power imbalance between Cas and Dean. Mind the warnings and kinks in the tags.
> 
> Anonymous said to omegadeanlovesalphacas:  
> I thought that Dean could be like an assassin!omega and has the order to seduce mafia boss!Castiel and kill him. They meet in a club for example and go somewhere for sex but they are true mates and mate each other. Instead of killing Castiel Dean becomes his omega and assassin and does kill his enemies for him.
> 
> Commissioned as a thank you to my very first patron!

Dean checked his hair in the rearview mirror right before he slipped out of his car. He looked good, he knew that he did. Tight jeans, tight black shirt, boots laced up to his knees. He was dressed to fuck.

And ready to kill.

He stopped and ducked into a doorway, checking his weapons. Small caliber gun at the small of his back and a knife in his boot. The only two weapons he ever needed.

Dean was an assassin. He’d been contracted to kill one Castiel Novak, the rival mafia boss of his employer. He’d been told he’d be at this club tonight, and that he had a weak spot for male omegas. All Dean had to do was seduce him, get him alone, then finish the job.

It would be easy.

Dean took a breath and adopted the air of a slinky, submissive omega. One who knew when to bear his neck and when to bend over. That always got him anywhere he needed to go.

He slipped up to the bouncer, who caught Dean’s very fertile scent and waved him inside without checking his ID. Dean just smiled bashfully at him and ducked his eyes, just like the submissive little omega he was pretending to be.

Once inside the club, Dean’s next target was the VIP section. It would be easy.

Dean walked up to the bar and ordered a drink, then sat on the stool and watched the dance floor, adopting the air of a nervous omega waiting to be approached by a handsome Alpha. A few did, coming up and asking him to dance, and Dean just blushed and turned them down, waiting for his target.

The next Alpha was the one Dean was looking for. He was a burly man in a suit, and when his eyes found Dean he gave him a cool appraisal and a smirk, before approaching. This was definitely Castiel’s man, scoping out companions for his boss.

“You’re a pretty thing,” the Alpha rumbled, stepping in close to Dean.

Dean glanced up, then ducked his face submissively with a blush. “Oh, thank you…” he mumbled, faking it perfectly.

“I’m Benny, what’s your name?” the Alpha asked.

“D-dean,” he mumbled, still not making eye contact, but leaning in a little closer, feigning interest.

“Have you been here before?” Benny asked.

Dean just shook his head.

“Well it’s a little drab down here on the main floor,” Benny said with a chuckle. “But I could get you upstairs, if you want. There’s lots of handsome Alphas up there, powerful Alphas with good money, who would be very interested in a pretty omega such as yourself. Would you be interested in meeting Alphas like that?”

Dean’s eyes grew wide with fake shock as he looked up at Benny, even as he crowed inside. “A-alphas?” He stuttered. He blushed and bit his lip, ducking his eyes again. “I… I guess that would be nice, if you think they’ll like me…”

“Oh they’ll love you,” Benny said, smiling and putting a hand on Dean’s arm. He took his drink and put it down on the bar. “Just leave it, we have an open bar upstairs.” He tugged Dean from the stool and started to lead him towards a guarded door.

Dean pretended to be nervous and unsure of himself as Benny guided him past the VIP bouncers–who leered at Dean quite blatantly, clearly they knew what Dean was chosen for–and up the stairs. When they stepped through the doors on the second floor, Dean’s eyes quickly scanned his surroundings.

The room was big, but still smaller than the main floor below them. The furniture up here was clearly very expensive, everything was set up with impeccable taste. The scent alone told Dean that there were several powerful Alphas in the room, as well as many very beautiful omegas. Most of the Alphas had an omega with them, some of the them sat with two or three.

“I think my boss would like to meet you,” Benny said, and he started to lead Dean over to a dark corner of the room.

Dean spotted Castiel Novak easily, the alpha was even more handsome in person than he had been in the picture Dean had been provided. He was currently sitting with a beta, having a rather serious conversation by the looks of it. But when he looked up at Benny’s approach his bright blue eyes flashed with interest, and he quickly sent the beta away.

“Just what do we have here?” Castiel asked, deep voice rumbling with his interest as he took in the sight of Dean. “For me?”

Dean blushed and ducked his head, pretending to be embarrassed but pleased. He couldn’t help the spark of real attraction to the Alpha, but he pushed it away and focused on his task.

Get the man alone. Kill him.

“Come sit with me,” Castiel said, smiling and holding a hand out to Dean.

Dean offered Castiel a pretty smile and reached out to take the Alpha’s hand. The man surprised Dean and tugged him down onto his lap, and Dean let out a soft giggle, pretending to be embarrassed by the forward Alpha.

And that was when Dean caught the Alpha’s scent. It was _amazing_ , unlike any Alpha he’d ever scented before. He couldn’t help but lean in, breathing a little deeper.

He was his mate. His _true_ mate. The man he was contacted to kill was his _mate._

Dean looked up at Castiel in shock, and he could see the lust and realization in the Alpha’s eyes. Castiel reached out and cupped Dean’s face in his hands, and leaned in for a gentle kiss, then dove in deeper, claiming and exploring.

Dean could only moan into the kiss, submitting to whatever the Alpha wanted of him. He wasn’t acting anymore, god, he _wanted_ this.

Castiel pulled back, staring at Dean intently. “What’s your name, little omega?”

“Dean,” he breathed, licking his lips, tasting the Alpha there.

“I’m Castiel,” the Alpha replied, considering Dean some more. He then seemed to suddenly make up his mind. “Come,” Castiel said, pulling away and putting Dean on his feet so he could stand. He took Dean’s hand in his with a firm grip and lead Dean towards a dark hallway.

Dean could only follow, still reeling from what his instincts were telling him.

_Submit. Alpha. Mate!_

No! Kill him! He’s your mission!

Castiel stopped at the door and turned to take Dean’s face in his hands and kiss him deeply, before he reached to open the door and tug Dean in after him into a bedroom. The Alpha easily picked Dean up with strong hands cupping his ass, carrying him across the room and dumping him on his back on the bed.

Dean gasped and spread his legs in invitation. There was no way he was going to be able to kill this beautiful Alpha.

Castiel closed and locked the door, turning to Dean with dark eyes as he tugged off his clothes. “You’re my mate,” he growled. “And I’m going to claim you.”

“Yes Alpha,” Dean gasped out, feeling eager slick flowing free from his channel, ready to take his true mate’s knot. “Please, wanna be yours.”

Castiel kicked off the rest of his clothes and climbed up over Dean, diving in to kiss him again. “What an eager little slut, can’t wait to get my cock in that slick little hole,” he growled, hand reaching down to unbutton the omega’s jeans while his mouth bit and sucked at Dean’s neck. “I bet you’ve already soaked through these jeans, haven’t you?”

Dean couldn’t help but moan and he nodded. “Yes, please Alpha!” He gasped as Castiel’s hard cock pressed into his hip, a promise of what was to come.

All thoughts of why he was here were long gone, all Dean knew was the Alpha above him and his desperate need to please him.

Castiel growled and sucked at Dean’s neck, leaving his mark and his scent behind. His hands started to roam, exploring Dean’s body. They trailed down his chest and encircled his small waist, starting to push his shirt up and off.

Then Castiel’s hands found the gun holster at the small of Dean’s back and he froze. With an angry snarl he ripped the gun out and threw it across the room, then swiftly grabbed Dean’s wrists and pinned them above his head.

“What the fuck was that?” He snarled, baring his teeth at Dean.

Dean whimpered and bared his neck to the angry Alpha in submission. “I-I’m sorry Alpha,” he gasped out. “Please, I’m sorry!”

Castiel’s eyes narrowed at Dean. “Were you sent to kill me?” he demanded.

“Y-yes Alpha,” Dean admitted, not meeting the Alpha’s eyes. “But I changed my mind!” He quickly added. “I promise, Alpha!”

Castiel’s angry expression faded and he smirked down at Dean. “You changed your mind because you realized you want to be my bitch,” he said, ducking his head to nip at Dean’s neck, more sharply then before.

Dean gasped, arching his back up toward the Alpha. “Yes!”

“You’re a needy little cock slut and you want to be owned, don’t you?” Castiel demanded. Pulling back again to look down at Dean.

Dean moaned, more slick leaking readily. “Yes, Alpha, please! Need to be yours!”

“My what?” Castiel demanded harshly, grinding his hard cock into Dean’s hip again.

“Your bitch!” Dean gasped out. “Your cock slut!”

“What a good little whore,” Castiel said, eyes tracking down Dean’s body. “What other weapons are you carrying?” he demanded.

“Just a knife, in my right boot,” Dean answered, obediently. “That’s all.”

Castiel held both of Dean’s wrists in one hand while he reached back with the other and pulled the knife free. He tossed it over where the gun had landed, then climbed off the omega.

Dean whimpered at the loss of the Alpha, reaching for him as he left.

“No,” Castiel snapped, standing several feet away from the bed. “Show me you’re a good slut, and weapon free, strip down and present yourself.”

Dean hurried to comply, pulling off his clothes and kicking off his boots, then flipped over on his face and pressed his ass up high. He spread his legs so that Castiel could see his eager, dripping hole.

Castiel growled at the sight, and he stalked back to the edge of the bed. He bent down and nipped hard at the round swell of Dean’s ass, making him yelp. “I’m going to breed you up and make you mine, just like a good bitch deserves. Do you want that, little slut?”

Dean moaned and nodded into the bed. “Yes, Alpha, please!”

Castiel didn’t need any more encouragement, and he climbed back on the bed behind Dean, lining his cock up to the omega’s slick entrance and pushing in. Dean’s body didn’t need any preparation, just the scent of his true mate had been all his body needed to be ready.

Dean cried out in pleasure as the Alpha– _his_ _Alpha–_ thrust into him, immediately setting a steady pace. Dean was unable to do anything but beg, “Yes Alpha. please, harder!” as Castiel fucked him.

“So desperate, so needy,” Castiel growled, gripping Dean’s hips tightly as he slammed into him. “You need my knot, don’t you little slut? You need to be filled up and bred.”

“Oh yes, Alpha,” Dean moaned, delirious with pleasure as the Alpha’s knot started to swell and drive into his prostate. “I need your knot, Alpha, please! I need to be bred up, I wanna be a good bitch for you, Alpha!”

Castiel just snarled and slammed in harder, making the omega under him howl with need and pleasure as he drove towards his knot. It finally swelled and slammed into place, tying the two of them together, and they both came hard with long, satisfied moans.

With a pleased growl, Castiel leaned in and bit down hard on Dean’s neck, claiming the omega as his own.

* * *

Castiel sat in his favorite seat in the VIP section of his club. He was talking a little business with Benny, but he wasn’t paying attention.

His beautiful mate had returned from his mission.

Dean strode confidently across the room, headed right for Castiel. He wore a very similar outfit to the one he’d worn the night they’d met, six months earlier. And Castiel had a little déjà vu when Dean slunk over and dropped into his lap with a pleased little smile.

“The mission is complete, Alpha,” Dean said, giving Castiel a cheeky grin. “He’s dead.”

Castiel smiled, pleased. “Good. Did it go smoothly?”

“Yep,” Dean squirmed a little on his Alpha’s lap, already eager to escape to the back room with him. “He thought he was gonna get to fuck me, but it didn’t work out that way.” He batted his eyelashes up at Castiel in a playful manner. “I was a good bitch and killed him before he got to take what was yours.”

Castiel grinned and raised an eyebrow at Dean. “What’s mine?”

“All of me is yours,” Dean said, beaming and pressing into his Alpha. “I was a good little slut for you, Alpha, can I please have my collar back?”

Castiel smiled and nodded, reaching into the briefcase next to his chair and pulling out Dean’s beautiful black collar. It was unfortunate that Dean had to take it off when he went on hunts, but it was difficult for a collared omega to seduce an Alpha. As it was it was hard enough for Dean to hide his claiming bite.

Castiel buckled the collar around the omega’s neck and pressed a kiss to the mating mark on his mate’s skin.

“Thank you, Alpha,” Dean murmured, letting out a content purr and cuddling into his Alpha’s strong chest. “Just want to be your good bitch tonight.”

Castiel smiled, gently running a hand through Dean’s soft hair. “You are, Dean. You are.”

 

**Author's Note:**

> Thanks for reading! Comments are love! <3
> 
> Visit me on Tumblr: [omegadeanlovesalphacas.tumblr.com/mobilemenu.](http://omegadeanlovesalphacas.tumblr.com/mobilemenu)


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